Methods and systems are provided for assisting operation of a vehicle using speech recognition. One method involves automatically identifying an input element based at least in part on an audio communication with respect to the vehicle, identifying one or more constraints associated with the input element, obtaining a limited command vocabulary for the input element using the one or more constraints, and automatically constructing a contextual speech recognition graph for the input element prior to user selection of the input element using the limited command vocabulary. Thereafter, subsequently received audio input is recognized using the contextual speech recognition graph that was automatically and prospectively generated.